An EcoModder first: "drag racing" (side-by-side coastdown competition)

[bgd73]

new definition for drag race.

I am reminded of a crank pulley that was mistorqued on a 2wd subaru, came right off the engine and sat there held up by the once spinning belts..lost water pump, alternator, power steering...

it glided for six miles, up and over a highway hill..and never went below 65mph.

I posted of this a few years ago...

A bimmer had a similar story, a certain few years of thier six model...

the subes definiton was easy, the 2wd retained the heavy flywheel, as the four drive....little buggy kept right on going. the boxer was the 3 main bearing, self balanced.(no external balances)

the bimmer story written remained a mystery.

I see the porsche flat six hybrid is playing with similar...not ferdinands choice of the six, but idea is still there..use an engine that can balance itself. Bigger than aero.....

[cfg83]

Frank -

Originally Posted by Frank Lee

Would have been interesting to do the "drag" run, then fill the "losing" car up with people/stuff and do it again...

If you could weigh the cars, then you could add weight to the lighter car to match the heavier car. Alternatively, you could calculate the gain of the heavier car and assign the proper handicap.

CarloSW2

[RobertSmalls]

This is a fun contest of coasting ability, which is road load divided by mass:

m*a=.5*CdA*ρ*V²+m*Crr*V

Winner has the lowest a.

At very low speeds, where I've won gravity-powered races against a coworker's '59 Plymouth and completely dominated his '64 Ford, it's strictly a contest of Crr.

When I first got the Insight, I was expecting it to coast forever. But it turns out, the Subaru coasts just as well due to its 50% higher mass and 50% higher road load.

[dcb]

my motorcycle does not coast well at higher speeds, light and not streamlined (tires are pumped up as much as I care to). The saturn glides much farther at higher speeds.

Funny thing is in rc sailplanes they can add weight to make them glide faster but it doesn't have much effect on the glide ratio. Of course it is harder to climb when you are heavier so the extra weight isn't a freebie.

[MetroMPG]

I suggested a variation of the contest on a long, relatively steep downhill run: a "terminal velocity" coasting competition would have been interesting. Also doing a CRR comparison from rest, by gravity.

But that road, while devoid of traffic, was only 2 lanes, so not as safe. Or socially acceptable, if we'd glided past local residences side by side.

Besides, Will had to hit the road and head back to NY.

[Big Dave]

Frank's right. You'd need weight classes. Otherwise we'd see Aerohead put 1,500 lbs of dense freight in his truck and coast into the next county. No penalty for all that energy needed to get him up to speed.

Big wheels are also bigger "flywheels."

On flat terrain, I can coast the better part of a mile 70-40.

Weight classes.

But a capital idea nevertheless.

[cfg83]

MetroMPG -

All good ideas. I am still looking for that lonely legendary "Ecomodder Hill + a long flat".

I have also thought of taking two Ecomodder mobiles to the drag strip to do "safe" coastdowns. Probably need signage on the side to keep the spectators from throwing too many tomatoes, .

CarloSW2

[NeilBlanchard]

You know, this is just like an "adult" version of soapbox derbies! Those people have it all figured out -- computer timing, the ramp, etc.

[MetroMPG]

True, true. Gravity racing would be best.

[Piwoslaw]

Originally Posted by Big Dave

Frank's right. You'd need weight classes. Otherwise we'd see Aerohead put 1,500 lbs of dense freight in his truck and coast into the next county. No penalty for all that energy needed to get him up to speed.

What about this: Both cars are weighed right before the race, then they accelerate to the top speed and switch off their engines. After they coast past the finish line they stop and get weighed again. The difference is the amount of fuel used to accelerate and that can be factored into the penalty.